b 1. Field Of The Invention PA1 2. General Background
The present invention relates to orthopedic surgical instruments and more particularly to an intramedullary rod targeting device in form of a drill guide that is useful in the attachment of an intramedullary nail and associated bone screws to the femur of a patient. Even more particularly, the present invention relates to an improved radiolucent drill guide having a handle portion of radiolucent material and a guide barrel that is imbedded within the handle in such a manner as to resist rotation and/or extrusion from the handle and wherein the barrel does not rotate freely relative to the handle, the handle preferably being molded (eg. injected molded) to the barrel after the barrel is constructed. The apparatus defines a target line which begins at the lateral cortex of a femur, through diagonal openings in the proximal end of an inserted intramedullary femoral rod, through the femoral neck and into the femoral head.
Intramedullary nails are commonly used to repair fractures at various positions on a patient's femur. For example, the intramedullary nail can be placed in a fractured femur with bone screws placed transversely through the femur and through openings in the intramedullary nail. U.S. Pat. No. 4,805,607 issued to Brumfield discloses an intramedullary nail for the repair of long bone fractures. Sometimes, the openings are diagonally placed. For example, U.S. Pat. No. 4,827,917 discloses an intramedullary nail that includes both transverse and diagonally extending openings through which bone screws can be placed as part of an overall repair. U.S. Pat. No. 4,827,917 is hereby incorporated herein for reference.
During an operative procedure, the surgeon places the intramedullary nail within the intramedullary canal of the patient's femur. Thereafter, holes must be drilled in precise locations through the patient's bone tissue and in alignment with the holes that are already a part of the intramedullary nail. A problem with this type of intramedullary nail surgery is the alignment problem. The bone screws must be precisely positioned relative to existing openings in the intramedullary nail. Therefore, targeting devices have been used in the art to insure proper placement of a bone screw relative to the intramedullary nail that has been installed in the patient's intramedullary canal.
A universal guide for inserting parallel pins is disclosed in the Kent Wu patent 4,570,624. The apparatus includes an elongated bar and a plurality of blocks slidable along the bar and adapted to be adjustable locked in position on the bar. Each block supports a transverse opening, the openings in the blocks being parallel to one another. In one form a removable sleeve is provided and has a complimentary external configuration corresponding to the internal configuration of the opening of each block. Each sleeve has an opening therethrough such that when the sleeves are positioned in the openings in the blocks, the openings of the sleeves are parallel to one another. Each sleeve has a serrated end for engagement with a bone of a portion of the body for holding the sleeve in position during drilling of an opening and insertion of a surgical pin.
An intramedullary rod targeting device for drilling of distal fastener screw passages in the femur of a patient during the installation of an intramedullary rod is disclosed in U.S. Pat. No. 4,881,535 issued to Gary Sohngen.
The Robert Border patent 4,911,153 entitled "Orthopedic Surgical Instrument discloses an instrument that serves as an adjustable guide for drills, reamers, fasteners and other orthopedic devices which lie on a target line which extends from the lateral cortex of the femur, through an opening in the proximal end of an inserted intramedullary nail, through the femoral neck and into the femoral head. The instrument can be secured to align with the inserted nail. A handle of the instrument extends downwardly from the top of the nail along the line which is substantially parallel to the target line.
The Rozas patent 4,978,351 provides a guiding instrument to pierce the bone cortical auxiliary in the location of the holes for intramedullary pins.
An intramedullary rod screw guide for use in orthopedic surgical procedures involving the installation of an intramedullary rod is disclosed in U.S. Pat. No. 5,047,034 issued to Sohngen. The Sohngen patent includes a device for attaching the guide to an external support assembly during installation of an intramedullary rod. A laterally extending spacer plate and intramedullary rod attachment at the proximal end of the spacing plate is provided, and a guide is secured to the spacer plate intermediate the proximal and distal ends thereof. The guide forms a passage which in use is lined with bone screw passage in the intramedullary rod permitting the guided insertion of drill means and bone screw insertion means through the guide passage in alignment with the bone screw passage in the intramedullary rod.
One example of a targeting device is U.S. Pat. No. 5,178,621 entitled "Two-Piece Radio-Transparent Proximal Targeting Device for a Locking Intramedullary Nail", issued to Kevin Cook and Karl Ousley. The Cook, et. al. device discloses a targeting device that includes a radio-transparent handle and a metal snap fit barrel. The radio-transparent handle reduces obstructions in the radio-graphic image to provide a clearer image to the surgeon for proper placement of the locking screws. The metal snap-fit barrel is retained in the handle by an interference fit between the handle and biased keys carried by the barrel. After use, the barrel may be easily disassembled for cleaning by striking a removal tool against the keys to drive the barrel from the handle.
An adjustable drill guide for use with an orthopedic implant having sleeves which are adjustable to accommodate misalignment of the sleeve relative to the bores within a prosthetic implant is the subject of U.S. Pat. No. 5,207,682 issued to Philip Cripe. Each sleeve is press-fitted within a retaining ring. The retaining rings are carried within a longitudinal slot of the extending leg of the guide. The rings may be clamped against movement after adjustment of the sleeves.
A published PCT application (PCT application number W0 93/11713) discloses a pilot device for a drill, for making the drilled hole for receiving a screw to be inserted into the neck of a femur, an intramedullary nail already being inserted into the femur. The apparatus includes a pivotable drilling template adjustable for height removably fitted at the proximal end of the intramedullary nail and having at least two drilling holes at a horizontal distance from each other of at least the diameter of the intramedullary nail.